One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,7)(3,6,8,5)(9,10)(11,15)(12,19)(13,14)(16,21)(17,22)(18,24)(20,23)(25,26,30,31)(27,29,33,37)(28,32,35,38)(34,36,39,40)(3,8)(5,6)(10,14)(11,17)(16,19)(18,20)(28,35)(32,38)(34,39)(36,40) involution — undirected(1,3,4,8)(2,5,7,6)(10,14)(11,17)(16,19)(18,20)(26,31)(27,33)(32,38)(34,39)(1,3)(2,5)(4,8)(6,7)(9,10)(11,15)(12,16)(13,14)(17,22)(18,23)(19,21)(20,24)(25,27)(26,29)(28,34)(30,33)(31,37)(32,36)(35,39)(38,40) involution — undirected(1,3)(2,6)(4,8)(5,7)(9,11,13,17)(10,15,14,22)(12,20,21,18)(16,24,19,23)(25,28,30,35)(26,32,31,38)(27,34,33,39)(29,36,37,40)(1,2)(3,5)(4,7)(6,8)(9,12)(10,16)(11,18)(13,21)(14,19)(15,23)(17,20)(22,24)(25,29)(26,27)(28,36)(30,37)(31,33)(32,34)(35,40)(38,39) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.